Electric controller.



G. B. DUSINBERRE.

ELECTRIC OONTROLLER. APPLICATION FILED JANA, 1910.

Patented Sept. 10, 1912 2 SHEETS-SHEET 1.

G. B. DUSINBEERE.

ELECTRIC CONTROLLER.

APPLICATION FILED JAN. 4, 1910.

Patented Sept. 10, 1912.

2 SHEETS-SHEET 2.

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ELECTRIC CONTROLLER.

To all whom it may concern:

Be it known that I, Gnonen B. DUSIN- nnnnn, a citizen of the UnitedStates, residing at Cleveland, in the State of Ohio, have inventedcertain new and useful Improvements in Electric Controllers, of whichthe.

following is a specification.

My invention relates generally to the control of electrical currents,and especially to the type of controller employing piles of resistanceelements with variable contacts,

of which the total resistance is varied by changing the pressurethereon.

The primary objects of my invention are, to equalize the dissipation ofenergy by a number of such resistance piles; to make the variation ofresistance correspond with variation in movement of the pressure device; to attain a stable balance between several resistance piles inparallel; to provide limiting devices to prevent excessive applicationof current to the controller; and

to operate such resistance devices directly,

by fluid pressure, without loss of motion and with great certainty.

I have illustrated the invention in one form in the accompanying drawingwherein- Figure l is a diagram andpartial section showing'several setsof resistance piles in parallel and the individual elements of the setsin series, one form of a current limiting device, and a mastercontrolling switch. Fig. 2 is a similar diagram representing amodification. Fig. 3 is a diagram illustrating resistance and pressurecharacteristic curves, to be hereinafter explained.

In devices for governing the current used for operating a motor forexample, ithas been proposed to use, instead of a number of fixedresistances which are cut in and out, step by step, a variableresistance device composed of a pile of carbon disks in which theresistance is gradually changed by varying the pressure upon the pile,thereby varying the contact between sepa rate disks of the pile. It willbe understood that such resistance elements have a limited capacity andit is sometimesnecessary to subdivide the elements and to mul- I tiplythe number of piles in order to put space.

them in commercially applicable form and In such case, in order thateach of the subdivisions may dissipate approximately the same amount ofenergy with equal current, the pressure upon various Specification ofLetters Patent.

Application filed January 4, 1910.

Patented Sept. 10, 1912.

Serial No. 536,284.

similar piles must be at all times equal. I provlde means for directlyand exactly equalizing pressures by use of fluid pressure; inconnectionwit-h which I employ a gas or air chamber which I have foundto vary in volume with variation of pressure, at approxima ely the sameratio that the carbon piles vary in resistance with variation ofpressure thereon. 1

Referring first to Fig. 3, it will be ob served that if the line 0 A betaken to represent resistance changes, and the line 0 B volume changes,then the curve 0 X will represent the resistance variation due to changeof volume in a gas, approximatelya straight line. Also if the line 0 Crepresents volume changes and the line 0 D represents the pressurechanges corresponding, the curve C D will represent actual variation involume resulting from variation in pressure. Again, on coordinates O Aand A D I have found by experiment that curve A D represents change ofresistance With pressure, in a column of carbon disks. That is to say,the curve of variation of resistance in the carbon pile correspondsapproximately to the curve of variation of volume of air with change ofpressure; from which it will appear that by using a gaseous medium toapply pressure to the carbon pile, or using other fluid pressureconnected with a gas chamber, it will be possible by equal displacementsof a pressure controlling diaphragm on the fluid to produceapproximately equal changes of resistance in the carbon pile.

Considering the left half of Fig. 1, it will i be noted that'I haveshown a controller comprising three parallel sets of variable resistancepiles: or columns 4:, the individual piles being connected in series ineach set. Considering first the'matter of varying resistances of thesein-such a way as to dissipate the same amount of energy by each one. ofseveral sets of piles 4, it will be observed that I employ a pressurechamber 5 comprising an expansible bellows, supporting a pressure bar 6and its interior space being connected by a pipe 7 and branches 8 and 9leading to compensating devices and conducting fluid pressure to thecolumns 4. Thus, the pipe 8 is connectedto a double bellows, 10, 11,'having two expans'ible chambers separa ted by a diaphragm 12 and the lowerchamber. 11 communicates through pipe 13 with all the expansion chambers14,

in the corresponding set of piles and governing the pressure .on thepiles 4, which it will he understood are pressed upward against a fixedabutment 15. The piles &. are connected in series as shown, and on oneside lead to the main line 16 going to the motor M, and on the otherside lead to the motor by line 17. This lead, however, passes through asolenoid 18, so that by reason of the movable core 19 thereof, and thearm 20 that the wiring for theseeonnects them parallel in the motorcircuit 16, 17. The

pressure on all the compensating chambers 10, 10', l0.,is the same andthereforeordr narily the pressure on all twelve of the columns 4; wouldbe the same. If however, for any reason, the resistance of the fourcolumns 4 tothe left of Fig. 1, should be less than normal under givenpressure, the current through the coil 18 will increase, whereupon theupward lift of the lever 20 on the diaphragm 12 of the compensatingchamber 10, 11, will reduce the pressure on the piles 42 of this groupand therefore raise the resistance to its proper value. This alsoincreases the pressure on the system 10, 10, 10, and so on the piles ofthe other sets, thus t-nding to maintain an electrical balance b tweenthe sets. So with each of the group and it will thus be seen that thedevice a tomaticallyc uses the several groups .of res stance piles todissipate the same amoun of energy. In some cases it may enrr ploy acompensator for each individual pile in a group, constructed inpraotically the same way as described In order that excessive currentmay not be thrown upon the motor, I use a current limiting device shownin one form at the left bottom of Fig. 1. The current from a mastercontroller orswitch passes directly by wire 21 through a pile of carbonblocks 22 and through a solenoid coil 23, and. by

lead 2 1, direct to the master switch 31 hereafter to be described. Bythis means the master controller electrically operates the pressure arm6 to govern the fluid pressure in the chamber 5. The main current fromthe resistance piles however, passes through a solenoid 25 whose core 26operates to re lease pressure on a spring 27 normally exerting pressureon the pile 22 and thus re ducing its resistance. From this it willappear that if an excessive current be thrown on, it will have theimmediate efiect of introducing a resistance at 22, cutting roeasao downthe current that passes through solenoid 23 operating the pressureresistance piles, and this reducing pressure on the piles 4., preventing1 excessive flOW-guflf the main current. This main currentalso passesthrough solenoid 28 whose movable core 29 is connected to the pressurearm 6, and in order to counterbalance the pressure on the severalcompensator chambers 10 inuse for convenience in operating the motorcontroller'at a distance. The handle 31 is pivoted at 32 and by means ofa cam and movable platform 33 it introduces pressure on a column ofcarbon blocks 3 1 when thrown to either side, for reversing. From themains 35 and 36, the current may pass to contact 37, through the handleto contact 88, to solenoids 39 and 40, through the resist-- tance pile34c and thence to the main resistance controller by lead 24. Solenoids39 and 40 close the switches 41 and 42 respec tively direct to the motorM. Similarly when the handle is thrown to the right, the

motor is reversed by similar action of solenoids 43, and 44, andswitches -l5 and 46. It will be clear that the distance the handle 31 isthrown over will, by varying pressure on column 34-, change the currentin leads 21, 23, thus varying the pressure in chamber 5 and thecompensating chambers 10 of the principal resistance piles; It isobvious that other means may be employed for controlling this auxiliarycurrent passing through the limiting resistance 22 and operatingsolenoid 23, such as a resistance of the usual wire constructionl And ofcourse the main switches may be manually operated.

In Fig. 2, I have shown a modification for operating directly, by thehandle 47, the fluid pressure in bellows as, and pipes 53 altering theresistance in chambers 49 of the resistance piles 50, which areconnected in circuit as desired and have device in the bellows 51 and asolenoid 52 carrying the total current for the purposes heretoforedescribed. I also show a lever" 54 with two cams which may alternatelybe used in place oflever at? and diaphragm 18.

a compensating This operates to induce pressure on, the chamber 55inducing pressure in the chambers 49 and thence on the pile-s50; thevalve 58 being closed in such operation. "in this prising a resistancevariable by'pressure and Copies of this patent may be obtained for form,it will be understood that the spring 57 corresponds in function tospring 27 in Fig. 1 and the solenoid 52 to solenoid 25 therein. a I jHaving thus described m inventiongand' illustrated'its use, I claim tefollo'fving:

1. An electric controller comprising I v u'al pressures .on all of saidreslstanceof resistance elements whoseresistancesi areg variable bypressure, and a fluid equalizer to impress pressure thereom. ineluding-a" compensating device to cause theseveral col-f umns to dissipatethe same'jamount of ena ergy.

2. An electric controller; in" -several resistance elements in gqghi,fithe'resistfl We is Variable Pr s +iee in ducing fluid pressure 'zib illgai Q68. I and s. s pe e ;by the Current; w

maintain theresistanaes-equal, substantially as described. .1-:.

3. An electric controller com rising sevi eral resistance elenients inwhic the ance is variable by pressure, means for in ducing fluidpressure on all said devices; and compensators operated by the current"to maintain the resistances equal, and means-'. to equalize changes offluid pressuredue to operation of the'compensators.

4. The combination with a variable pres-- sure resistance dev1ce,ofmeans for inducing fluid pressure thereon including a volume ofr,

gas, acting as part of the operating fluid body.

5. The combination with a resistance controller, of a current limitingdevice comcompensating means for varying the pressure thereon, operatedby the total current,

6. The combination of a master controller;v

a resistance variable by pressure and means circuit containing a currentlimiting device operated by the main current.

The combination with severa resistancepiles whose resistances are variedby pressure, of a master diaphragm and a fluid chamber and connectionsadapted to impress es. 8. ,The combination with a circuitincludingaresistance variable by pressure, of a current limiting devicecomprising a solenoid adapted to change the pressure on said,res'istance, inversely with changes oi: current strength."

'.9.' Thecombi'nati on ofa current controller consistin Ofr'fi series ofresistance elements variable ypressure'thereon, electric meansZtorcOntmhsuch pressures, a compensating device to balance the pressureson the severalresistanceelements inversely as the current therethrough,a master switch and a current'limiting device acting automatically,prevent throwing excessive current on the said tresistances.

10. In a current series of sets of resistance elements variablebyapressure thereon, the combination of 'fluid' meanselectrically'operated to induce pressure .on said resistance elementsand an amounts of energy to be absorbed by each of said sets ofresistance elements.

In "testimony whereof I have .'hereunto t ed 111 'name in the presenceof the two su scri .vvitnessesf 1 enonen n nusmnnann. Y .Witnesses:- -I'v 5 JAsaW Bnsmaa, v

operated by the master controller to ,vary

Washington, n. c.

pressure on said resistance, and an auxiliary controller comprising aautomatic compensator to cause equal

